1. Field of Invention
The invention relates to electrical and electro-optical module packaging designs. The invention more particularly relates to a module housing apparatus that temporarily houses an electrical or electro-optical module.
2. Description of Related Art
Electrical and electro-optical modules present difficult challenges to a packaging engineer. Such modules include one or more circuit boards with various electrical, optical, and/or electro-optical components. Such modules are quite fragile and should be adequately protected during shipping, servicing, or at an other time when the module is not located within a permanent or other protective container. The types of protection required by such modules include physical protection and ESD (electrostatic discharge) protection.
Many manufacturers of such modules utilize a permanent container to house sensitive boards having electrical, optical, and/or electro-optical components. For example, a common solution is to use a sheet metal housing to fully enclose the board(s).
While a sheet metal container does provide a measure of physical and electrostatic discharge (ESD) protection, such permanent containers create their own problems. Chief among these problems is heat dissipation. By enclosing the board(s) within a sheet metal container, thermal mass increases and, perhaps more significantly, airflow is restricted. Thus, the heat generated by the components is much harder to dissipate and may contribute to component failure, degradation and shortened life-span. Openings, holes and fans are often added to cool the components but such techniques are often inadequate and may lead to ESD problems.
Another problem of permanent containers is that they consume valuable space. A common goal in the electronics and opto-electronics industries is to produce modules of minimum size. The permanent container solution consumes space and defeats this goal. Moreover, the permanent container adds a level of complexity and cost to a module which can be a serious disadvantage in an industry having narrow profit margins.
Another common solution is to dispense with a permanent housing altogether. This creates shipping and temporary storage problems for the unprotected module. As noted above, the module is subject to physical damage as well as ESD damage from improper handling.
Various temporary module packing designs are commercially available to solve these problems. A typical design is a plastic clamshell enclosure in which two plastic panels with a common hinge may be closed in a clamshell fashion to house a module. The plastic panels usually have an cavity that conforms to the exterior dimensions of the module being housed. Such clamshell enclosures are quite flimsy and fail to adequately protect the module being housed. To provide the necessary physical protection such clamshell enclosures are themselves enclosed in other protective packaging materials particularly during shipping. This adds bulk, expense and may contribute to ESD problems particularly if electrically insulative packaging materials are used.
Suspension packaging is another conventional packing design widely used in the industry. Such suspension packages include two frames each of which holds a sheet of resilient material such as thin plastic. The module is put between the two frames which are then brought together thereby trapping the module between the resilient sheets. The space between the module and external box housing the frames provides a measure of physical protection but this measure may not adequate to protect the module. In addition, the plastic sheets and paper materials used are typically insulative and create ESD problems which can damage the components of the module.
Furthermore, suspension packaging is cumbersome and bulky and may not be utilized by a technician seeking a temporary home for the module. For example, such suspension packages are typically used only for shipping and are thrown away after shipping due to their bulk and not available for a temporary housing solution.
Therefore, there is a need for a module housing that solves the above-identified and other problems in the industry.
To achieve these and other objects of the invention, a module housing apparatus is disclosed for housing a module having at least one circuit board and a faceplate to which the circuit board is attached, including a box having an open end and a conductive outer surface; and a module board guide on an inside surface of the box, the module board guide having at least one slot along a longitudinal direction thereof, the slot being dimensioned to accept an edge of the circuit board of the module.
Although only one module board guide is necessary it is preferable to use a pair of the module board guides provided on opposing inside surfaces of the box, each of the module board guides having at least one slot along a longitudinal direction thereof, the slot being dimensioned to accept an edge of the circuit board of the module.
The module board guide may be an integral structure of the box or may include a pair of inserts attached to opposing inside surfaces of said box, each of said inserts having at least one slot along a longitudinal direction thereof, the slot being dimensioned to accept an edge of the circuit board of the module.
The module board guide may also have an insertion guide on a leading surface thereof facing the open end of said box and connected to said slot, the insertion guide guiding the edge of the circuit board into the slot.
Conductive materials such are preferably used to construct the box in order to have the desired Faraday cage effect. To complete the Faraday cage, the faceplate of the module is also preferably a conductive material.
Moreover, the leading edge of the module board guide may be shaped to accept the profile of the module. For example, the module board guide may be shaped to have a recess formed on a leading surface thereof facing the open end of the box, the recess dimensioned to accept a holding clip of the module faceplate.
Furthermore, the module board guide may have a plurality of slots along a longitudinal direction thereof, each of the slots being dimensioned to accept a corresponding edge of the circuit board of the module.
To further protect the module, a front resilient cap may be removably attached to the open end of the box and having an inside surface that substantially conforms to an outside surface of the module faceplate.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.